A027675 When squared gives number composed of digits {1,4,9}.

1, 2, 3, 7, 12, 21, 38, 107, 212, 31488, 70107, 387288, 95610729, 446653271, 3148717107, 21081079479, 648070211589107021

Offset: 1

Author

Patrick De Geest

Keywords

• nonn
• base
• more

Comments

If a number has a least significant digit of 0, 4, 5 or 6, it can't be in this sequence. - Alonso del Arte, Jun 11 2016

Examples

			Since 107^2 = 11449, 107 is in the sequence.
As 108^2 = 11664 has two 6's, 108 is not in the sequence.
		

Links

• Chris, Three Digits Solution, June 29, 2005.
• Patrick De Geest, Squares containing at most three distinct digits, Index entries for related sequences
• Patrick De Geest, Palindromic Squares in bases 2 to 17
• A. Ottens, The arithmetic-digits-squares-three.digits problem [broken link].
• Eric Weisstein's World of Mathematics, Square Number.

Crossrefs

Cf. A006716.

Programs

Mathematica

Select[Range[100], Complement[IntegerDigits[#^2], {1, 4, 9}] == {} &] (* Alonso del Arte, Jun 11 2016 *)